In recent years, monitor screens of digital devices have migrated from cathode-ray tubes to liquid crystals and recently to LED liquid crystals. However, liquid crystal monitors, especially LED liquid crystal monitors, intensely emit short-wavelength light of approximately 430 to 450 nm, called blue light. Thus, in order to effectively mitigate asthenopia or ocular pain which occurs due to long time use of digital devices, it is desirable to take measures against blue light. Note that, blue light is light having the wavelength of 430 to 450 nm in the following description.
In this regard, JP 2012-093689 A or its English family member U.S. 2013/222913 A1, the disclosure of which is incorporated herein in its entirety especially by reference, proposes an optical product including a multilayer film having a characteristic of reflecting light having the wavelength of 400 to 450 nm including the wavelength range of blue light.